1. Field of the Invention
The present invention relates to the field of multihop mobile wireless networks and, more particularly, to a method for finding and reserving bandwidth in multihop mobile wireless networks.
2. Description of Related Art
Multihop mobile (or ad hoc) wireless networks can be rapidly deployed without the support of fixed infrastructure. Each node in the network acts as a router as well as a host. The nodes are free to move randomly and organize themselves arbitrarily. Therefore, the topology of the network may change rapidly and unpredictably. These networks are found in applications such as disaster relief, military operations, and short-term activities.
In the multihop mobile wireless networks, the CDMA (Code Division Multiple Access) spread spectrum modulation technique is used for the radio channels and each channel is slotted by the TDMA (Time Division Multiple Access). Mobile nodes within two hops are assigned different spreading codes to avoid the hidden terminal problem.
Bandwidth reservation is essential in supporting Quality of Service (QoS) in multihop mobile wireless networks. To reserve bandwidth along a path from a source node to a destination node, the available bandwidth (in terms of number of data slots) of the path need to be found first in order to determine whether the requested bandwidth can be satisfied. The sufficient number of data slots on each of the links-along the path are reserved.
In a time-slotted network, finding the available bandwidth of a multihop path is known to be a NP-complete. A conventional heuristic method uses the DSDV (Destination-Sequenced Distance-Vector) routing algorithm to find and reserve the available bandwidth in a hop-by-hop manner starting from the destination node toward the source node. However, because the available common free slots of the next hop are unknown in the process, it is likely to find a bandwidth smaller that the actual available one due to the lack of network information. Therefore, it is desirable to provide an improved method to mitigate and/or obviate the aforementioned problems.